Concentric Laser Module / Precision Laser Module - Quarton Inc.
Resources - LaserLinc
Amazon.com: Quarton Red Dot Laser Module CLM-635-11 LPO (Concentricity Laser Module, Precision Laser Module), Class I Laser, less than 0.39mW : Industrial & Scientific
HL-40 Universal Punch Concentricity Gage
Concentricity (GD&T) Explained | Fractory
What is Geometric Dimensioning and Tolerancing (GD&T)?